The primary function of peripheral nerves is to connect the central nervous system with target organs, and also play a role of conveying information. Peripheral nerves contain internal nerve fascicles, the internal nerve fascicles of peripheral nerves can be divided into sensory fascicles, motion fascicles and mixed fascicles. The primary functions of these nerve fascicles are to afferent and efferent information. It is well known that the most optimal repair methods in clinical is to achieve anastomosis between functional fascicles once an injury or defect of human peripheral nerves occurs. However, since the anatomical structure of human peripheral nerve fascicles is quite complicated, a precondition for clinicians is understanding of the anatomical structure law and morphology of fascicular type of human peripheral nerves in order to achieve a goal of anastomosis between functional fascicles. A visualization model of internal fascicular structure obtained for reconstruction of human peripheral nerve three-dimensional structure is expected to provide an effective method for improving the functional recovery after peripheral nerve defect.
On the other hand, three-dimensional reconstruction of human peripheral nerve fascicles also holds a more far-reaching significance, with the development of modern bio-manufacturing technology, biomimetic manufacture of many tissues and organs has already been achieved. But it is very difficult to achieve the biomimetic manufacture of peripheral nerves, the reasons are chiefly as follows: {circle around (1)} the internal structure of nerves is complicated and fine, the required precision cannot be achieved using the existing bio-manufacturing methods; {circle around (2)} each piece of, and even each segment of nerve fascicle has its own corresponding biological functions, which have not been fully understood for the present. The visualization model of three-dimensional reconstruction of peripheral nerve fascicles will solve the above problems being faced during bio-manufacturing of peripheral nerve biomaterials, namely to achieve a standard of precision medicine.
In terms of three-dimensional reconstruction of peripheral nerve fascicles, many scholars have done a lot of research, for example, understanding of three-dimensional anatomical structure of human nerve fascicles by Sunderland has undergone the following process: it was initially regarded as frequently crossing on the same plane, whereas at present it is observed that vascular network is formed at its proximal end, and at its distal end fascicles are frequently mixed or divided into several small fascicles. Jian Qi et al. reconstructed a three-dimensional structure of the median nerve using the histological section method on peripheral nerves, at the same time they also found the complexity in configuration of nerve fascicles. However, all these methods of reconstructing three-dimensional anatomical structure of peripheral nerve fascicles have their own disadvantages, such as inadequate precision in acquiring two-dimensional structure, bad matching in the course of reconstruction, image distortion and involvement of abundant anthropic factors. Therefore, it is quite necessary to seek a simple and effective technical method which is capable of capturing two-dimensional images with high resolution and simultaneously achieving a successive matching at the three-dimensional level.
With the development of modern technology, computed tomography (CT) and magnetic resonance imaging (MRI) have become the major imaging means for three-dimensional reconstruction. But because the internal structure of peripheral nerves are relative fine, such scanning precision cannot be achieved using the existing MRI. Therefore, it is urgent currently to find a method to construct a visualization model for internal fascicles structure of human peripheral nerves and to implement a three-dimensional reconstruction of human peripheral nerves.